G3 PLC Overview

1. G3 PLC Overview Speaker : Shih-Chi Huang Advisor : Dr. Kai-Wei Ke 2014/04/07

2. Outline • PLC Background • G3 PLC Aims • G3 PLC Communication Profile • Physical Layer • MAC Layer • Network and Transport Layer • Application Layer • Conclusion

3. PLC Background • 電力線通訊是透過一般的電源插座當作網路連接阜，使用電力線當作訊號傳輸的媒介，電力線通訊一般簡稱為PLC(Power Line Communication)。

4. PLC Technology • 傳送端利用正交分頻多工(OFDM)技術將用戶資料加以編碼與調變，然後在電力線上進行資料傳輸， • 在接收端首先經過電力線耦合器及高頻濾波將調變信號濾出，並經解碼與解調變之後，就可得到原來通訊信號。

5. PLC Networks System 主要可分為兩大部分 • Access BPL (Access PLC) • In-House BPL (In-House PLC )

6. PLC Category 根據頻寬的不同又可分為 • 超窄頻電力線通訊(Ultra Narrowband PLC)，超窄頻的頻率範圍為 0.3 kHz 至 3 kHz • 窄頻電力線通訊(Narrowband PLC)，窄頻的頻率範圍為 3 kHz 至 500 kHz • 寬頻電力線通訊(Broadband PLC)，寬頻的頻率範圍為1.8 MHz 至 250 MHz 窄頻電力線通訊的傳輸速度小於1Mbps，是用於長距離的傳輸 寬頻電力線通訊的傳輸速度大於1Mbps，是用於短距離的高速傳輸。

7. Compare PRIME with G3

8. G3 PLC PROFILE SPECIFICATION

9. G3 PLC Aims • Robustness : 通訊功能適合在極其嘈雜的環境下工作，如低壓電力線、中壓電力線的長距離通訊，尤其支援 MV-LV 變壓器間的通訊。 • Performance: 雙向數位通訊，傳輸速率最高為300Kbps。 • Simplicity : 易於執行、安裝(即插即用)、操作和維修。 • Flexibility : 相容不同的應用和網路拓撲結構。 • Security:AES-128 密碼引擎確保環境安全。 • Compatibility: 相容於已經存在的系統。 • Scalability: 支援 IPv6，可用於新的網際網路能源管理系統和應用。

10. G3 PLC Communication Profile

11. Physical Layer Two functional blocks : • The Physical processing block (PHY) in charge of emission and reception over the PLC medium • The PHY Management Entity (PLME) responsible for managing the PHY layer. It relies in particular on the PHY Information Base (PHY PIB).

12. Physical Layer (Cont.) The Physical Layer Management Entity (PLME) comprises the following functions : • Carrier detection : This is one of the important elements of the CSMA/CA procedure. • Phase detection : It allows identification of the phase on which the meter transmits. • Management of the PHY PIB Information Base

14. MAC Layer Two functional blocks : • The MAC Common Part Sublayer(MCPS) responsible for communication with the neighbouringnodes • The MAC Layer Management Entity (MLME) responsible for management of the MAC sublayer. It relies in particular on the MAC PAN Information Base (MAC PIB) whose main element is the Neighbour Table. This table contains all the information that the MAC and PHY levels need for bidirectional communication with the neighbours.

15. MAC Layer (Cont.) The MAC Sublayer Management Entity (MLME) features the following functions : • Active discovery (active scan) of neighbouring nodes. • Management of the MAC level parameters. These parameters constitute the MAC Information Base (MAC PIB). • Initialization/Reinitializationof the MAC and PHY layers.

16. 6LoWPAN Adaptation sublayer • In order not to compromise the speed of the OFDM PLC links, the IPv6 and UDP headers are compressed.[rfc4944] Reduces the IPv6 and UDP headers from 48 bytes to 5 bytes. • Calculation of the optimum route between two nodes A and B of the PLC LAN using the LOADprotocol

18. Network And Transport Layer • Network layer is based on the IPv6 protocol to ensure the long-term continuity of the model. • Transport layer is UDP which provides unreliable transport to datagrams in non-connected mode. Reliability of exchanges within the PLC network is brought by the subjacent layers. • Other compression schemes shall be usable if necessary, such as adaptive ROHCv2 compression [rfc4995] with its specific profiles for TCP/IP [rfc4996] and UDP/IP [rfc5225]. In most cases ROHCv2 manages to reduce header size to 2 bytes.

20. Application Layer The Applications stratum covers layers 5 to 7 in the OSI model. The model proposed for metering is somewhat simplified and comprises two broad classes of Applications : • Metering Application • Meter Management Application It will be noted that all these applications rely natively on UDP.

21. Metering Application In the OFDM PLC profile the COSEM (能源計量配表規範) Application strictly complies with the existing standards, namely : • "COSEM Application Part" such as it is defined in [IEC 62056-61] and [IEC 62056-62] • "COSEM Application Layer" such as it is defined in [IEC 62056-53] • Security at Application level is ensured by the process defined in [Blue Book].

22. Metering Application (Cont.) Transport of the COSEM Application protocol by UDP requires the interpositioning of a "Wrapper" in accordance with [IEC 62056-47]

23. Meter Management Applications The Meter Management Applications feature three large functional blocks: • A Management Agent • A Software Downloading system • An Initialization and Supervision system

24. Management Agent The Management Agent operates under the supervision of a Manager function. they must address the different functional domains : • Configuration Management, which allows the loading and reading (GET/SET) of the parameters that control the functioning of the Meter. • Fault and Alarm Management which ensures the supervision of functioning of the meter, the detection, recording and signalling of faults which are presented as Alarms • Statistics Management, which counts and logs all the marking events

25. Management Agent (Cont.) The protocol used for exchanges between Management Agent and Manager is SNMP (Simple Network Management Protocol) in its latest version [rfc3416]. The security functions of SNMPv3 [rfc3414] turn out to be relatively difficult to use. To maintain simplicity of deployment, it is preferable not to activate them and to rely on the security functions offered by the OFDM PLC MAC level.

26. Software Downloading system • The firmware memory images are stored in a File Server. • The recommended downloading protocol is TFTP (Trivial File Transfer Protocol) [rfc1350]. It is usually used for unicastdownloading, but a multicastversion [rfc2090] is also specified.

27. Compare FTP with TFTP

28. Software Downloading system (Cont.) The downloading mechanism proper is that defined by the BroadBandForum. It provides for two methods: • Unmanaged downloading : The file server contacts the equipment directly by sending it a TFTP Write-Request (WRQ) message. In this case the transfer can only be unicast. • Managed downloading : the Managers sets the necessary parameters in the equipment (URL of file to download, timeout, etc.) then gives the equipment the order to start the downloading. The equipment then contacts the file server by sending it a TFTP RRQ (Read-Request) message. Transfer can then take place in unicast or multicast mode after negotiation. The server can accept it by returning a TFTP OACK (Option-Acknowledge) message.

29. Software Downloading system (Cont.) The Memory Image files thus transferred must have the following characteristics: • They must be natively in S format [rfc4194]. • They must be compressed to GZIP format [rfc1952]. • Each packet comprises: • A header including a preamble, the type of packet (version) and the lengths of the list of commands and of the payload. • description, version, role of the file, actions on the file system, timeouts, bootstrap, etc. • A block of signatures • The payload which contains one or more files.

30. Initialization and Supervision system This system is responsible for sequencing the actions when bootstrapping the meter, such as "active scan", launching of the LBP/EAP/EAP-PSK protocol suite for authentication, distributing the keys and the initial configuration.

31. Conclusion Benefits brought by the OFDM PLC profile : • Data rates : 30kb/s for DQPSK modulation，15kb/s for DBPSK modulation • MAC level Security : they are simple，sincetheybasedonauniqueproof of identity (a 128-bit shared secret) and a single cryptographic algorithm (AES-128) • Architecture diversity and openness (IP) : can use IPv6 • Open Equipment Management (SNMP) : which reduces the acquisition and operating costs, as is witnessed by its widespread adoption by Network operators. • Software (Firmware) management (TFTP) : Another example of the benefits brought by the introduction of Internet technologies is the use of standard protocols and tools for the downloading and management of firmware.

32. Thanks for Listening